Power station, facts about power stations

Electricity is our most important source of power, but we cannot
yet produce it directly from a natural source of energy, such as
coal or water. First we must convert this energy into mechanical
power to spin an electrical generator. This is what happens in a
power station.

The two most important kinds of stations are those which burn fuel
to produce steam and those which harness the energy of falling
water. (See
Famous dams). In these stations, the steam or
the rushing water spins turbines which are connected to the
generator.

Power station, facts about power stations

In a power station, heat energy is converted into electrical energy. The heat may be derived from burning coal or from
nuclear fuel. But whatever the source of heat, hot gases turn water in the boiler tubes into steam which passes into the turbine. The revolving shaft of the turbine drives the generator. The steam condenses and is returned to start the cycle again

Two-thirds of the world's power stations are steam-operated. The
most common fuels are coal and oil. They are burned to heat water in
boilers to produce steam at a high temperature and pressure.

Several countries have nuclear power stations which use uranium
as nuclear fuel. Heat is produced when the uranium atoms split. (See
Facts about nuclear energy). Thereafter, it is used to produce steam and spin
turbines as in conventional stations.

Once the electricity has been produced, it must be distributed to
consumers many miles away. This is done through cables, or
transmission lines, usually carried above ground on pylons. The
voltage, or 'pressure', of the electricity produced by the generator
is not high enough for transmission over long distances. Therefore,
it is 'stepped up' by a device called a transformer. It is
transmitted in this form to local sub-stations which step it down
low enough to be used by the consumer.

Power station, facts about power stations

Giant turbines are used to drive
generators in power stations, producing enormous quantities of
electricity.

The various power stations in a region, or even a country, are
connected with one another by what is called a grid system of power
lines. This means that electricity from one station can be sent to
another when the other is overloaded.

Included in the grid are small, standby stations that are
used only at times of peak demand, when the system is overloaded.
Many have generators powered by diesel engines or gas turbines,
which can be started up at short notice.